On Fri, Aug 6, 2021 at 10:52 AM Miklos Szeredi <miklos@xxxxxxxxxx> wrote: > > On Thu, 29 Jul 2021 at 07:27, Amir Goldstein <amir73il@xxxxxxxxx> wrote: > > > Given that today, subvolume mounts (or any mounts) on the lower layer > > are not followed by overlayfs, I don't really see the difference > > if mounts are created manually or automatically. > > Miklos? > > Never tried overlay on btrfs. Subvolumes AFAIK do not use submounts > currently, they are a sort of hack where the st_dev changes when > crossing the subvolume boundary, but there's no sign of them in > /proc/mounts (there's no d_automount in btrfs). That's what Niel's patch 11/11 is proposing to add and that's the reason he was asking if this is going to break overlayfs over btrfs. My question was, regardless of btrfs, can ovl_lookup() treat automount dentries gracefully as empty dirs or just read them as is, instead of returning EREMOTE on lookup? The rationale is that we use a private mount and we are not following across mounts from layers anyway, so what do we care about auto or manual mounts? Thanks, Amir.